NON-UNIFIED STRAIN CRITERIA FOR CONCRETE UNDER MULTIAXIAL STRESSES

Strain criteria sensitive to the octahedral normal and shear strains for concrete subjected to multiaxial stresses are developed. The proposed nonunified criteria are formulated for the elasticity limit (at 50% of peak strength) and for the continuity limit (at 70% of peak strength) of concrete. Four of formulations, which showed acceptable agreement with experimental data, were tried and those providing satisfactory correlation are presented. Use is made of the results of a series of extensive tests on concrete under short term monotonic loading, Reformed by the various investigators, and fifty-six sets of data are given in table form. These criteria include uniaxial, biaxial and triaxial compression and also biaxial compression-tension, biaxial tension-tension and uniaxial tension stress states. The proposed criteria can be incorporate in the prediction of both the elasticity and continuity limits of concrete material by a constitutive model.